09 - Life-Span Development

ENDURING ISSUES IN LIFE-SPAN DEVELOPMENT

In trying to understand human development, psychologists primarily focus on three enduring issues.

1. Individual characteristics versus shared human traits (Diversity-Universality). We all take essentially the same developmental journey, but each of us travels a different road and experiences events in different ways. Barack Obama's life illustrates this well. Like other people, he progressed through the stages of childhood, adolescence, and adulthood; he embarked on a career, developed a number of close friendships, and dealt with the normal challenges of growing up to become a mature adult. These are all common developmental milestones. Yet in other ways, Obama's development was not like everyone else's. Not everyone grows up in such an unstable, multicultural family, a child of divorce who is ultimately left in the care of his grandparents, goes to elite schools and colleges, or achieves such professional heights. This combination of shared and distinctive elements is common to human development.

2. Stability versus change (Stability-Change). The extent to which our thoughts, behaviors, and personalities remain stable or change throughout life's journey is also of central concern to developmental psychologists. Again, Obama's life is an excellent example. The move back to Hawaii to live with his supportive grandparents was certainly a major turning point in his development. Attending Columbia University and Harvard Law School also had a profound effect upon him. And yet with all the changes that these transitions brought, we still see many of the qualities he displayed as a young child in Indonesia.

3. Heredity versus environment (Nature-Nurture). There is probably no issue of more importance to developmental psychologists than the nature-nurture question. How do biological and environmental forces interact to shape human behavior and growth throughout the life span? Obama's parents were both intelligent. Even in the first grade he showed unusual signs of leadership. But his gifts might have gone undeveloped if his mother hadn't enrolled him in the Punahou school and his grandparents had not supported and encouraged him. How different might he have been had he been born into a different family or chosen a different life's work?

METHODS IN DEVELOPMENTAL PSYCHOLOGY

As developmental psychologists study growth and change across the life span, they use the same research methods used by psychologists in other specialized areas: naturalistic observations, correlational studies, and experiments. But because developmental psychologists are interested in the processes of change over time, they use these methods in three special types of studies: cross-sectional, longitudinal, and biographical.

In a cross-sectional study, researchers examine developmental change by observing or testing people of different ages at the same time. For example, they might study the development of logical thought by testing a group of 6-year-olds, a group of 9-year-olds, and a group of 12-year-olds, looking for differences among the age groups. However, one problem with cross-sectional studies is that they don't distinguish age differences from cohort differences, which are due to the fact that individuals were born and grew up during different historical times. All Americans born in 1960, for example, form a cohort. If we find that 40-year-olds are able to solve harder math problems than 80-year-olds, we wouldn't know whether this difference is due to better cognitive ability in younger people (an age difference) or to better math education 40 years ago (a cohort difference).

Longitudinal studies address this problem by testing the same people two or more times as they grow older. For instance, researchers who are interested in the development of logical thought might begin their study by testing a group of 6-year-olds, then test the same children again at age 9, then test them again at age 12. One potential problem with longitudinal studies is that they may not distinguish age differences from differences caused by using different assessment or measurement tools. For example, researchers retesting a cohort at age 12 would probably use a different measure of logical thought than they did when they tested that cohort at age 6. So if they found significant improvement in logical thought over this 6-year period, they wouldn't know to what extent it reflected the advance in age and to what extent it reflected the difference in measuring tools.

Another drawback to a longitudinal study is that it takes considerable time. When studying the entire life span, a longitudinal study would take decades to complete. To avoid the huge expense of such a long study, researchers have devised a third way of studying adulthood: the biographical (or retrospective) study. With this approach, the researcher might start with some 70-year-olds and pursue their lives backward by interviewing them and consulting other sources. However, biographical data are less trustworthy than either longitudinal or cross-sectional data, because people's recollections of the past may be inaccurate.

PRENATAL DEVELOPMENT

During the earliest period of prenatal development - the stage of development from conception to birth - the fertilized egg divides, beginning the 9-month process that will transform it from a one-celled organism into a complex human being. Two weeks after conception, the cells begin to specialize: Some will form the baby's internal organs, others will form muscles and bones, and still others will form the skin and nervous system. No longer an undifferentiated mass of cells, the developing organism is now called an embryo.

The embryo stage ends 3 months after conception, when the fetal stage begins. At this point, although it is only 1 inch long, the fetus roughly resembles a human being, with arms and legs, a large head, and a heart that has begun to beat. The mother's blood vessels transmit nutritive substances to the embryo or fetus, and carry waste products away from it through the placenta. Although the mother's blood never actually mingles with that of her unborn child, toxic agents that she eats, drinks, or inhales (known as teratogens) are capable of crossing the placenta and compromising the baby's development. Diseases can also cross the placenta and harm the fetus.

There is a critical period during prenatal development when many substances are most likely to have a major effect on the fetus. At other times, the same substance may have no effect at all. For example, if a woman contracts rubella (German measles) during the first 3 months of pregnancy, the effects can range from death of the fetus to a child who is born deaf. If she gets rubella during the final 3 months of pregnancy, however, severe damage to the fetus is unlikely, because the critical period for the formation of the major body parts has passed.

Pregnancy is most likely to have a favorable outcome when the mother gets good nutrition and good medical care, and when she avoids exposure to substances that could be harmful to her baby, including alcohol and nicotine. Alcohol is the drug most often abused by pregnant women, often with devastating consequences such as fetal alcohol spectrum disorder (FASD), a condition characterized by multiple problems including cognitive impairments and brain damage (McBee, 2005; E. S. Moore et al., 2007; Paley & O'Connor, 2007). Even small amounts of alcohol can cause neurological problems (Irene Choi, Allan, & Cunningham, 2005). Nicotine is also harmful because it restricts the oxygen supply to the fetus, slows its breathing, and disrupts the regular rhythm of the fetal heartbeat (Zeskind & Gingras, 2006). These changes are associated with a significantly increased risk of miscarriage and low birth weight (Ness et al., 1999).

The mother's level of psychological stress during pregnancy and the way she copes with it also can affect the health of a newborn (Rothenberger, Resch, Doszpod, & Moehler, 2012). Research with several species of animals, including non-human primates, has shown that maternal distress increases the concentration of certain hormones in the mother raising the risk for learning, attention, and emotional impairments in the offspring (Emack, Kostaki, Walker, & Matthews, 2008; Kaiseer & Sachser, 2009; Weinstock, 2008). Studies with humans have also shown that the risks of prematurity and low birth weight were higher in mothers with low self-esteem who felt pessimistic, stressed, and anxious during pregnancy (Schetter, 2009; Schetter & Glynn, 2011).

THE NEWBORN

Research has disproved the old idea that neonates, or newborn babies, are oblivious to the world. Although newborns can sleep up to 20 hours a day, when awake they are much more aware and competent than they may seem at first glance.

Reflexes

Newborns come equipped with a number of essential reflexes. For example, the baby's tendency to turn his or her head toward anything that touches the cheek, called the rooting reflex, helps the baby find the mother's nipple. The sucking reflex is the tendency to suck on anything that enters the mouth; and the swallowing reflex enables the baby to swallow liquids without choking. Infants are also capable of reflexively imitating the facial expressions of adults (B. Bower, 2003b). For example, if an adult sticks out his or her tongue, newborn babies often respond by sticking out their tongues. And from the very beginning, infants can communicate their needs: They can cry. After only about 6 weeks they have an even better method of communication: They can smile.

Temperament

Babies display individual differences in temperament from the time they are born. Some cry much more than others; some are much more placid. Some babies love to be cuddled; others seem to wriggle uncomfortably when held.

To some extent these differences in temperament appear to be hereditary. But there is also some evidence that prenatal factors play a significant role (Huizink et al., 2002; Susman, Schmeelk, Ponirakis, & Gariepy, 2001). In particular, maternal stress produces reliable changes in heartbeat and movement in the fetus; these, in turn, have been correlated with temperament (Gutteling et al., 2005).

Regardless of what initially causes a baby's temperament, it often remains stable even into adulthood (McAdams & Olson, 2010). A combination of biological and environmental factors contributes to this stability in behavior. For instance, if a newborn has an innate predisposition to cry often and react negatively to things, the parents may find themselves tired, frustrated, and often angry. These reactions in the parents may serve to reinforce the baby's difficult behaviors, and so they tend to endure. In other cases, environmental factors can cause basic changes in temperament. Thus, a child born with a particular temperament will not necessarily have that temperament for life. Each child's predispositions interact with his or her experiences, and how the child turns out is the result of that interaction (Booth-LaForce & Oxford, 2008; Hane, Cheah, Rubin, & Fox, 2008).

Perceptual Abilities

Infants begin to absorb and process information from the outside world even before they enter it. Research shows that in the last few months before birth, fetuses hear and remember songs, some key aspects of their parents' native language, and even entire words (Moon, Lagercrantz, & Kuhl, 2013; Partanen et al., 2013).

Vision

Unlike puppies and kittens, human babies are born with their eyes open and functioning, even though the world looks a bit fuzzy to them at first. They see most clearly when faces or objects are only 8 to 10 inches away from them. Visual acuity (the clarity of vision) improves rapidly, however, and so does the ability to focus on objects at different distances. By 6 or 8 months of age, babies can see almost as well as the average college student, though their visual system takes another 3 or 4 years to develop fully.

Even very young babies have visual preferences. They would rather look at a new picture or pattern than one they have seen many times before. If given a choice between two pictures or patterns, both of which are new to them, they generally prefer the one with clearer contrasts and simpler patterns. As babies get older and their vision improves, they prefer more complex patterns (Acredolo & Hake, 1982; Fantz, Fagan, & Miranda, 1975; Slater, 2000).

In general, infants find human faces and voices particularly interesting (Flavell, 1999; Turati, 2004). Just a few days after birth babies can discriminate different facial expressions in adults. For example, they look longer at a happy adult face than a fearful one (Farroni, Menon, Rigato, & Johnson, 2007). They also will follow the other person's gaze. For example, when presented with a human face depicted as looking to the left or right, infants as young as 2 days old notice the direction of the adult's gaze and shift their gaze accordingly (Farroni, Massaccesi, Pividori, & Johnson, 2004). Newborns also prefer to look at their own mother rather than at a stranger (Bushnell, 2003).

Depth Perception

Although researchers have been unable to find evidence of depth perception in babies younger than 4 months, the ability to see the world in three dimensions is well developed by the time a baby learns to crawl, between 6 and 12 months of age.

This was demonstrated in a classic experiment using a device called a visual cliff (Walk & Gibson, 1961). Researchers divided a table into three parts, with a solid runway in the center. On one side of this runway was a solid surface decorated in a checkerboard pattern and covered with a sheet of clear glass. The other side was also covered with a thick sheet of clear glass, but on this side - the visual cliff - the checkerboard surface was not directly under the glass, but 40 inches below it. An infant of crawling age was placed on the center runway, and the mother stood on one side or the other, encouraging the baby to crawl toward her across the glass. All of the 6- to 14-month-old infants tested refused to crawl across the visual cliff, even though they were perfectly willing to cross the "shallow" side of the table.

Other Senses

Even before babies are born, their ears are in working order. They can hear sounds and will startle at a sudden, loud noise in the uterine environment. After birth, babies show signs that they remember sounds they heard in the womb. For example, immediately after birth, newborns prefer the sound of their mother's voice to that of an unfamiliar female voice (Kisilevsky et al., 2003).

Infants are particularly tuned into the sounds of human speech (T. M. Hernandez, Aldridge, & Bower, 2000). In some ways, young infants are even better at distinguishing speech sounds than are older children and adults. As children grow older, they often lose their ability to hear the difference between two very similar speech sounds that are not distinguished in their native language. For example, young Japanese infants have no trouble hearing the difference between "ra" and "la," sounds that are not distinguished in the Japanese language. By the time they are 1 year old, however, Japanese infants can no longer tell these two sounds apart (Werker, 1989).

With regard to taste and smell, newborns have clear-cut likes and dislikes. They like sweet flavors, a preference that persists through childhood. Babies only a few hours old will show pleasure at the taste of sweetened water but will screw up their faces in disgust at the taste of lemon juice (Rosenstein & Oster, 2005).

As infants grow older, their perceptions of the world become keener and more meaningful. Two factors are important in this development. One is physical maturation of the sense organs and the nervous system; the other is gaining experience in the world.

INFANCY AND CHILDHOOD

During the first dozen or so years of life, a helpless baby becomes a competent member of society. Many important kinds of developments occur during these early years.

Neurological Development

The human brain changes dramatically during infancy and early childhood. During the first 2 years after birth, children have heads that are large relative to their bodies as the brain undergoes rapid growth. A child's brain reaches three-quarters of its adult size by about the age of 2, at which point head growth slows down, and the body does most of the growing. Head growth is virtually complete by age 10, but the body continues to grow for several more years. Infants are born with approximately 100 billion neurons, though the number of connections between neurons immediately after birth is relatively small. During the first 2 years of life, however, dendrites begin to bloom and branch out; and the number of interconnections between neurons increases dramatically. The developing nervous system also sees the rapid growth of the myelin sheaths, the fatty covering that encases many neurons to provide insulation and increase the speed of conduction. With this rapid growth in the number of connections and speed, the developing brain has an enhanced potential to respond to new and varied experiences, which, in turn, further increases the number of connections between neurons.

As the number of interconnections between neurons increases during early childhood, the density of synaptic connections in the brain also swells dramatically. Synapses are areas where neurons communicate with one another. During infancy, synaptic growth is particularly prominent in the prefrontal cortex, which is involved in reasoning and self-regulation, and in the visual and auditory areas of the cortex. Surprisingly, in the third year of life there is actually a decrease in both the number and density of synaptic connections. this decrease appears to result from a natural process in which neurons that are stimulated and used grow stronger and more complex, while those that are unused are replaced or "pruned" away (Huttenlocher, 2002; M. S. C. Thomas & Johnson, 2008).

These patterns of neurological growth, complexity, and reorganization provide a striking example of how nature and nurture work together, underscoring the importance of early and varied stimulation during development. Indeed, a lack of stimulation during this early period of development can negatively impact the growth of neurons and the number of connections between them, adversely affecting development.

Physical and Motor Development

During the first year of life, the average baby grows 10 inches and gains 15 pounds. By 4 months, birth weight has doubled and by the first birthday, birth weight has tripled. During the second year, physical growth slows considerably. Rapid increases in height and weight will not occur again until early adolescence.

An infant's growth does not occur in the smooth, continuous fashion depicted in growth charts. Rather, growth takes place in fits and starts. When babies are measured daily over their first 21 months, most show no growth 90% of the time, but when they do grow, they do so rapidly. Incredible though it may sound, some children gain as much as 1 inch in height overnight!

Marked changes in body proportions accompany changes in a baby's size. During the first 2 years after birth, children have heads that are large relative to their bodies as the brain undergoes rapid growth. A child's brain reaches three-quarters of its adult size by about the age of 2, at which point head growth slows down, and the body does most of the growing. Head growth is virtually complete by age 10, but the body continues to grow for several more years.

Motor development refers to the acquisition of skills involving movement, such as grasping, crawling, and walking. Much early motor development consists of substituting voluntary actions for reflexes. The newborn stepping reflex, for instance, gives way to voluntary walking in the older baby (Gallahue & Ozmun, 2006).

The average ages at which such skills are achieved are called developmental norms. By about 9 months, for example, the average infant can stand up while holding onto something. Crawling occurs, on average, at 10 months, and walking occurs at about 1 year. These ages are not exact; a baby who is 3 or 4 months behind schedule may be perfectly normal, and one who is 3 or 4 months ahead is not necessarily destined to become a star athlete. To some extent, parents can accelerate the acquisition of motor skills in children by providing them with ample training, encouragement, and practice. As coordination improves, children learn to run, skip, and climb. At 3 and 4, they begin to use their hands for increasingly complex tasks, such as learning how to put on shoes, then grappling with shoelaces. Gradually, through a combination of practice and physical maturation of the body and the brain, they acquire increasingly complex motor abilities, such as bike riding and swimming. By the age of about 11, some children begin to be highly skilled at such tasks (Gallahue & Ozmun, 2006).

Cognitive Development

The most influential theorist in the are of cognitive development was the Swiss psychologist Jean Piaget (1896-1980). Piaget observed and studied children, including his own three. As a result of his observations, Piaget believed that cognitive development is a way of adapting to the environment. In Piaget's view, children are intrinsically motivated to explore and understand things. As they do so, according to Piaget, they progress through four basic stages of cognitive development.

Sensory-Motor Stage (Birth to 2 years)

According to Piaget, babies spend the first 2 years of life in the sensory-motor stage of development. They start out by simply applying the skills with which they were born - primarily sucking and grasping - to a broad range of activities. Young babies delight in taking things into their mouths - their mother's breast, their own thumb, or anything else within reach. Similarly, young babies will grasp a rattle reflexively. When they eventually realize that the noise comes from the rattle, they begin to shake everything they can grasp in an effort to reproduce the sound. Eventually, they distinguish between things that make noise and things that do not. In this way, infants begin to organize their experiences, fitting them into rudimentary categories such as "suckable" and "not suckable," "noise making," and "not noise making."

Another important outcome of the sensory-motor stage, according to Piaget, is the development of object permanence, an awareness that objects continue to exist even when out of sight. For a newborn child, objects that disappear simply cease to exist - "out of sight, out of mind." The concept of object permanence is universal among all cultures.

By the end of the sensory-motor stage, toddlers have also developed a capacity for self-recognition - that is, they are able to recognize the child in the mirror as "myself." In one famous study, mothers put a dab of red paint on their child's nose while pretending to wipe the child's face. Then each child was placed in front of a mirror. Babies under 1 year of age stared in fascination at the red-nosed baby in the mirror; some of them even reached out to touch the nose's reflection. But babies between 21 and 24 months reached up and touched their own reddened noses, thereby showing that they knew the red-nosed baby in the mirror was "me" (Bard, Todd, Bernier, Love, & Leavens, 2006; Brooks-Gunn & Lewis, 1984).

Preoperational Stage (2 to 7 years)

When children enter the preoperational stage of cognitive development, their thought is still tightly bound to their physical and perceptual experiences. But their increasing ability to use mental representations lays the groundwork for the development of language - using words as symbols to represent events and to describe, remember, and reason about experiences. Representational thought also lays the groundwork for two other hallmarks of this stage - engaging in fantasy play (a cardboard box becomes a castle) and using symbolic gestures (slashing the air with an imaginary sword to slay an imaginary dragon).

Although children of this age have made advances over sensory motor thought, in many ways they don't yet think like older children and adults. For example, preschool children are egocentric; they have difficulty seeing things from another person's point of view. An illustration of egocentric behavior can sometimes be seen during the game of hide-and-seek, when young children cover their own eyes to prevent others from seeing them.

Children of this age are also easily misled by appearances. In a famous experiment, Piaget showed preoperational children two identical glasses, filled to the same level with juice. The children were asked which glass held more juice, and they replied (correctly) that both had the same amount. Then Piaget poured the juice from one glass into a taller, narrower glass. Again, the children were asked which glass held more juice. They looked at the two glasses, saw that the level of juice in the tall, narrow one was much higher, and then replied that the narrow glass had more.

Concrete Operational Stage (7 to 11 years)

During the concrete-operational stage, children become more flexible in their thinking. They learn to consider more than one dimension of a problem at a time and to look at a situation from someone else's viewpoint. This is the age at which they become able to grasp principles of conservation, such as the idea that the volume of a liquid stays the same regardless of the size and shape of the container into which it is poured. All related conservation concepts, such as those dealing with number or mass, involve an understanding that basic amounts remain constant despite superficial changes in appearance that can be reversed.

Another accomplishment of this stage is the ability to grasp complex classification schemes such as those involving superordinate and subordinate classes. For instance, if you show a preschooler four toy dogs and two toy cats and ask whether there are more dogs or more animals, the child will probably answer "more dogs." It is not until age 7 or 8 that children are able to think about objects as being simultaneously members of two classes, one more inclusive than the other. Yet even well into the elementary school years, children's thinking is still very much stuck in the "here and now." Often, they are unable to solve problems without concrete reference points that they can handle or imagine handling.

Formal-Operational Stage (Adolescence through Adulthood)

This limitation is overcome in the formal-operational stage of cognitive development, often reached during adolescence. Most, but not all, youngsters at this stage can think in abstract terms (Kuhn, 2009). They can formulate hypotheses, test them mentally, and accept or reject them according to the outcome of these mental experiments. Therefore, they are capable of going beyond the here and now to understand things in terms of cause and effect, to consider possibilities as well as realities, and to develop and use general rules, principles, and theories. Does this mean that adolescents should be held to the same legal standard as adults? The American Psychological Association has successfully argued before the Supreme Court that when deliberative, reasoned decision making is called for (such as medical and legal decisions), adolescents are as capable of mature decision making as adults. However, where high levels of emotional arousal or social coercion are involved and decisions must be made impulsively, adolescents are less mature than adults and thus less blameworthy (Steinberg, Cauffman, Woolard, Graham & Banich, 2009). Thus, in the eyes of the law, a 16-year-old adolescent is capable of deciding to have an abortion without consulting her parents, but a 16-year-old adolescent who commits a capital crime will not face capital punishment as an adult would for the same crime.

Criticisms of Piaget's Theory

Piaget's work has produced a great deal of controversy (Shayer, 2003). Many question his assumption that there are distinct stages in cognitive development that always progress in an orderly, sequential way, and that a child must pass through one stage before entering the next (Kagan, 2008). Some see cognitive development as a more gradual process, resulting from the slow acquisition of experience and practice rather than the abrupt emergence of distinctly higher levels of ability (Boom, 2004; Courage & Howe, 2002).

Piaget's theory has also sparked criticism for assuming that young infants understand very little about the world, such as the permanence of objects in it (Kiss, 2001; A. Woodward & Needham, 2009). When young babies are allowed to reveal their understanding of object permanence without being required to conduct a search for a missing object, they often seem to know perfectly well that objects continue to exist when hidden by other objects (Baillargeon, 1994). They also show other quite sophisticated knowledge of the world that Piaget thought they lacked, such as a rudimentary grasp of numbers, the ability to take the perspective of another person, and sophisticated reasoning (Gopnik, 2009; V. Izard, Dehaene-Lambertz, & Dehaene, 2008).

Other critics have argued that Piaget underplayed the importance of social interaction in cognitive development. For instance, the influential Russian psychologist Lev Vygotsky contended that people who are more advanced in their thinking provide opportunities for cognitive growth in children with whom they interact (Harree, 2000; Vygotsky, 1978). These learning experiences greatly depend on a society's culture, another factor that Piaget ignored (Siegal, 2003).

Despite these criticisms, Piaget's theory provides a useful schematic road map of cognitive development (Morra, Gobbo, Marini, & Sheese, 2008). Moreover, Piaget profoundly impacted our understanding with his observation that children play an active role in the learning process, his description of qualitative changes in the way children think at various ages, and his emphasis on "readiness to learn."

Moral Development

One of the important changes in thinking that occurs during childhood and adolescence is the development of moral reasoning. Lawrence Kohlberg (1979, 1981) studied this kind of development by telling his participants stories that illustrate complex moral issues. For example, in one of the best known of these stories, the "Heinz dilemma," a woman is described as near death from cancer. Her only hope for treatment requires that she be given a drug developed by a local pharmacist. However, the price of the drug is $2,000, despite that it only cost $200 for the pharmacist to make. Heinz, the woman's husband, can only raise half the money to purchase the drug, so he asks the pharmacist to sell him the drug for half the price or permit him to pay the remainder in installments. But the pharmacist says "No." Driven by desperation, the husband breaks into the pharmacy and steals the drug to save his wife (Kohlberg, 1969). The children and adolescents who heard this story were asked if the husband should have done what he did, and to explain the reason for their answer. On the basis of his participants' replies to these questions, Kohlberg theorized that moral reasoning develops in stages, much like Piaget's account of cognitive development.

• Preconventional level - Preadolescent children are at what Kohlberg called the preconventional level of moral reasoning: They tend to interpret behavior in terms of its concrete consequences. Younger children at this level base their judgment of "right" and "wrong" behavior on whether it is rewarded or punished. Somewhat older children, still at this level, guide their moral choices on the basis of what satisfies needs, particularly their own.

• Conventional level - With the arrival of adolescence and the shift to formal-operational thought, the stage is set for progression to the conventional level of moral reasoning. At this level, the adolescent at first defines right behavior as that which pleases or helps others and is approved by them. Around mid-adolescence, there is a further shift toward considering various abstract social virtues, such as being a "good citizen" and respecting authority. Both forms of conventional moral reasoning require an ability to think about such abstract values as "duty" and "social order," to consider the intentions that lie behind behavior, and to put oneself in the "other person's shoes."

• Postconventional level - The postconventional level of moral reasoning requires a still more abstract form of thought. This level is marked by an emphasis on abstract principles such as justice, liberty, and equality. Personal and strongly felt moral standards become the guideposts for deciding what is right and wrong. Whether these decision correspond to the rules and laws of a particular society at a particular time is irrelevant. For the first time, people may become aware of discrepancies between what they judge to be moral and what society has determined to be illegal.

Kohlberg's views have been criticized on several counts. First, research indicates that many people in our society, adults as well as adolescents, never progress beyond the conventional level of moral reasoning. Does this finding mean that these people are morally "underdeveloped," as Kohlberg's theory implies?

Second, Kohlberg's theory does not consider cultural differences in moral values. Kohlberg put considerations of "justice" at the highest level of moral reasoning. In Nepal, however, Buddhist monks place the highest moral value on alleviating suffering and showing compassion, concepts that have no place in Kohlberg's scheme of moral development (Huebner, Garrod, & Snarey, 1990). Nevertheless, research supporting Kohlberg has shown that there are some common moral values and basic moral judgment stages that are consistent across cultures (Boom, Wouters, & Keller, 2007; Gibbs, Basinger, Grime, & Snarey, 2007).

Third, Kohlberg's theory has been criticized as sexist. Kohlberg found that boys usually scored higher than girls on his test of moral development. According to Carol Gilligan (1982, 1992), this was the case because boys are more inclined to base their moral judgments on the abstract concept of justice, whereas girls tend to base theirs more on the criteria of caring about other people and the importance of maintaining personal relationships. In Gilligan's view, there is no valid reason to assume that one of these perspectives is morally superior to the other.

More recent research on moral development has moved in the direction of broadening Kohlberg's focus on changes in moral reasoning. Researchers are increasingly interested in the factors that influence moral choices in everyday life, and the extent to which those choices are actually put into action. In other words, they want to understand moral behavior as much as moral thinking (D. C. Reed, 2008; Tappan, 2006).

Language Development

The development of language follows a predictable pattern. By the time they are three months old, infants can make several sounds that express their emotions. Squeals and laughs reflect positive emotions, while growls and crying reflect negative emotions (Oller et al., 2013). In another month or two, the infant enters the babbling stage and starts to repeat sounds such as da or even meaningless sounds that developmental psychologists refer to as "grunts"; these sounds are the building blocks of later language development. A few months later, the infant may string together the same sound, as in dadadada. Finally, the baby will form combinations of different sounds, as in dabamaga.

Even deaf babies who communicate with sign language engage in a form of babbling. Like hearing infants, these babies begin to babble before they are 10 months old - but they babble with their hands! Just as hearing infants utter sounds over and over, deaf babies make repetitive movements of their hands, like those of sign language (Goldin-Meadow, 2003).

Gradually, an infant's babbling takes on certain features of adult language. At about age 4 to 6 months, the infant's vocalizations begin to show signs of intonation, the rising and lowering of pitch that allows adults to distinguish, for example, between questions ("You're tired?") and statements ("You're tired"). Also around this time, babies learn the basic sounds of their native language and can distinguish them from the sounds of other languages. By 6 months, they may recognize commonly used words, such as their own names and the words mommy and daddy.

By around their first birthday, babies begin to use intonation to indicate commands and questions. At about the same age, they show signs of understanding what is said to them, and they begin not only to imitate what others say but also to use sounds to get attention. Vocalization also becomes increasingly communicative and socially directed. Caregivers facilitate this process by speaking to babies in what is called infant-directed speech. They speak slowly and use simple sentences, a higher pitched voice, repetition, and exaggerated intonations - all of which engage babies' attention and help them distinguish the sounds of their language.

All this preparation leads up to the first word at about 12 months. During the next 6 to 8 months, children build a vocabulary of one-word sentences called holophrases: "Up!"; "Out!"; "More!". Children may also use compound words such as awgone [all gone]. To these holophrases, they add words used to address people - Bye-bye is a favorite - and a few exclamations, such as Ouch! These first words play an important role in the formation of the child's vocabulary and pave the way for their understanding of grammar.

In the second year of life, children begin to distinguish between themselves and others. Possessive words become a big part of the vocabulary: [The shoes are] "Daddy's." but the overwhelming passion of children from 12 to 24 months is naming. With little or no prompting, they will name virtually everything they see, though not always correctly! If they don't know the name of an object, they will simply invent one or use another word that is almost correct. Feedback from parents ("no, that's not a dog, it's a cow") enhances vocabulary and helps children understand what names can and cannot be assigned to classes of things ("dog" is not used for big four-legged animals that live on farms and moo rather than bark).

During the third year of life, children begin to form two- and three-word sentences such as "Baby cry" and "My ball." Recordings of mother-child conversations show that children from 24 to 36 months old noticeably omit auxiliary verbs and verb endings ("I [am] eat[ing] it up"), as well as prepositions and articles ("It [is] time [for] Sarah [to] take [a] nap"). Children this age seize on the most important parts of speech - those that contain the most meaning.

After 3 years of age, children begin to fill in their sentences ("Nick school" becomes "Nick goes to school"), and language production increases dramatically. Children start to use the past tense, by applying the regular form when an irregular one is called for (saying "Alex goed" instead of "Alex went," for example). Such mistakes are signs that the child has implicitly grasped the basic rules of language. Preschoolers also ask more questions and learn to employ "Why?" effectively and endlessly! By the age of 5 or 6, most children have a vocabulary of over 2,500 words and can construct sentences of 6 to 8 words.

Theories of Language Development

Several different theories explain how language develops. B. F. Skinner (1957) believed that parents and other people listen to the infant's cooing and babbling and reinforce those sounds that most resemble adult speech. If the infant says something that sounds like mama, mommy reinforces this behavior with smiles and attention. As children get older, the things they say must sound more like adult speech to be reinforced. Skinner believed that an understanding of grammar, word construction, and so on are acquired in much the same way.

Most psychologists and linguists now believe that learning alone cannot explain the speed, accuracy, and originality with which children learn to use language (Christiansen & Chater, 2008a, 2008b; Pinker, 1994, 1999). Noam Chomsky (1965, 1986) has proposed that children are born with a language acquisition device, an internal mechanism that is "wired into" the human brain that enables young children to detect general patterns of grammar in adult speech, thus permitting them to quickly learn the words and rules of any language to which they are exposed.

A more recent theory of language acquisition, advanced by Steven Pinker (1994, 2007; Pinker and Jackendoff, 2005), holds that, to a large extent, evolutionary forces may have shaped language, providing humans with what he calls a language instinct. Drawing extensively from the fields of linguistics, evolutionary psychology, and neurolinguistics, Pinker constructs a convincing case that language should not be viewed as a "cultural artifact." Instead, Pinker (1994) argues that language is "a distinct piece of the biological makeup of our brains" (p. 18). He contends, "people know how to talk in more or less the sense that spiders know how to spin webs" (p. 18).

According to Pinker, the language instinct, like other instincts, evolved through natural selection, taking the form of an innate circuitry in the brain that uses complex computational rules to perceive, organize, and transmit information (Pinker, 2007). It is because of this adapted circuitry, for instance, that humans are predisposed attach meaning to words, a process that cognitive neuroscientists recognize as exceedingly complex. According to Pinker, this circuitry also guides the language acquisition process, which enables children to attend to minor but important differences in the pronunciation of words, such as talk and talks, when they listen to adult speech (Pinker, 1999; 2004). This is important because only by focusing on the relevant aspects of speech could a child ever master the grammatical rules of a language.

Not everyone agrees with Pinker's position (Fitch, Hauser, & Chomsky, 2005; Karmiloff-Smith, 2002; Sampson, 1999). Critics are quick to point out that research has not yet identified any of the specific neural circuits that Pinker describes. They also contend that other theories, based more on learning than on instinct, can just as easily explain many aspects of human language.

Bilingualism

In the past two decades, psychologists have come to fully realize that the ability to speak more than one language is not unusual. For the great majority of people in the world, it is quite normal (Fields, 2012). As a result, research on the acquisition and use of multiple languages has not only expanded rapidly but it also sheds new light on the nature of language, the mind and the brain. It is now clear that, contrary to some earlier beliefs, exposure to multiple languages very early in life is not harmful but is, in fact, beneficial to children (Bialystok & Craik, 2010). It is also clear that bilingualism provides long-term benefits, specifically providing some protection from cognitive declines in old age (Bialystok, Craik, Green, & Gollan, 2009; Kroll & Bialystok, 2013).

In a comprehensive review of the research literature, Bialystok, Craik, Green, & Gollan (2009) draw the following conclusions:

• Bilingual children learn their languages in the same way as monolinguals, though as children and adults they have a smaller vocabulary in each language than do monolinguals.

• Bilinguals of all ages have better "executive control" which means the ability to control attention, ignore distractions, to switch between tasks, and to hold information in mind while performing a task.

• Bilinguals use the same brain networks for executive control as do monolinguals.

The fact that young children can learn a second language as easily and effortlessly as they acquire one language demonstrates the critical importance of the environment in which they are raised. The fact that children can learn a second language more quickly and speak it more fluently than adults supports the idea of a critical period during which languages are most readily acquired. Moreover, the languages to which a child is exposed during that critical period determine the languages in which the child will be truly proficient. This critical period starts to close with the onset of puberty (Sakai, 2005; Sakai & Muto, 2007), which is why it is difficult for even a young adolescent to learn to speak a second language without an accent (Flege, Munro, & MacKay, 1995).

Social Development

Learning to interact with others is an important aspect of childhood development. Early in life, children's most important relationships are with their parents and other caregivers. But by the time they are 3 years old, their important relationships have usually expanded to include siblings, playmates, and other adults outside the family. Their social world expands further when they start school.

Parent-Child Relationships in Infancy: Development of Attachment

Young animals of many species follow their mothers because of imprinting. Shortly after they are born or hatched, they form a strong bond to the first moving object they see. In nature, this object is most often the mother, the first source of nurturance and protection. But in laboratory experiments, certain species of animals, such as geese, have been hatched in incubators and have imprinted on decoys, mechanical toys, and even human beings (H. S. Hoffman & DePaulo, 1977; Lorenz, 1935). These goslings faithfully follow their human "mother," showing no interest whatever in adult females of their own species.

Human newborns do not imprint on first-seen moving objects, but they do gradually form an attachment, or emotional bond, to the people who take care of them. Classic studies of baby monkeys suggest that the sense of security engendered by physical contact and closeness is one component root of attachment (Harlow, 1958; Harlow & Zimmerman, 1959).

In humans, this attachment is built on many hours of interaction during which baby and parent come to form a close relationship. Signs of attachment are evident by the age of 6 months or even earlier. The baby will react with smiles and coos at the caregiver's appearance and with whimpers and doleful looks when the caregiver goes away. At around 7 months, attachment behavior becomes more intense. The infant will reach out to be picked up by the caregiver, and will cling to the caregiver, especially when tired, frightened, or hurt. The baby will also begin to display stranger anxiety, often reacting with loud wails at even the friendliest approach by an unfamiliar person. If separated from the caregiver for even a few minutes in an unfamiliar place, the baby will usually become quite upset. Stranger anxiety usually begins around 7 months, reaching its peak at 12 months, and then declines during the second year of life.

Parents are often puzzled by this new behavior in their previously nonchalant infants, but it is perfectly normal. In fact, anxiety over separation from the parent indicates that the infant has developed a sense of "person permanence" along with a sense of object permanence. For 5-month-olds, it's still "out of sight, out of mind" when Mom or Dad leaves the room, but for 9-month-olds, the memory of their parent lingers, and they announce at the top of their lungs that they want Mommy or Daddy to come back!

Ideally, infants learn in their first year of life that their primary caregivers can be counted on to be there when needed. Psychologist Erik Erikson (1902-1994) called this result the development of basic trust. If babies' needs are generally met, they come to develop faith in other people and also in themselves. They see the world as a secure, dependable place and have optimism about the future. In contrast, babies whose needs are not usually met, perhaps because of an unresponsive or often-absent caregiver, develop what Erikson referred to as mistrust. They grow to be fearful and overly anxious about their own security.

As infants develop basic trust, they venture away from the caregiver to investigate objects and other people around them. This exploration is a first indication of children's developing autonomy, or a sense of independence. Autonomy and attachment may seem to be opposites, but are actually closely related. The child who has formed a secure attachment to a caregiver can explore the environment without fear. Such a child knows that the caregiver will be there when really needed, and so the caregiver serves as a "secure base" from which to venture forth (Ainsworth, 1977; Dwyer, 2006).

At about 2 years of age, children begin to assert their growing independence. They refuse everything: getting dressed ("No!"), going to sleep ("No!"), using the potty ("No!"). The usual outcome of these first declarations of independence is that the parents begin to discipline the child. The conflict between the parents' need for peace and order and the child's desire for autonomy often creates difficulties. But it is an essential first step in socialization, the process by which children learn the behaviors and attitudes appropriate to their family and their culture.

Erikson saw two possible outcomes of this early conflict: autonomy versus shame and doubt. If a toddler fails to acquire a sense of independence and separateness from others, self-doubt may take root. The child may begin to question his or her own ability to act effectively in the world. If parents and other adults belittle a toddler's efforts, the child may also begin to feel ashamed. The need for both autonomy and socialization can be met if parents allow the child a reasonable amount of independence, while insisting that the child follow certain rules.

Parent-Child Relationships in Childhood

As children grow older, their social worlds expand. Erikson saw the stage between ages 3 and 6 as one of growing initiative, surrounded by a potential for guilt (initiative versus guilt). Children of this age become increasingly involved in independent efforts to accomplish goals - making plans, undertaking projects, mastering new skills - from bike riding to drawing to writing simple words. Parental encouragement of these initiatives leads to a sense of joy in taking on new tasks. But if children are repeatedly criticized and scolded for things they do wrong, they may develop strong feelings of unworthiness, resentment, and guilt. In Erikson's view, avoiding these negative feelings is the major challenge of this stage.

The effect of parenting style on a child's outlook and behavior has been the subject of extensive research. There are four basic parenting styles (authoritarian, permissive-indifferent, permissive-indulgent, and authoritative) and they affect developing children in different ways.

Although many studies show a relationship between parental behavior and child development, be cautious when drawing conclusions about cause and effect. Understand that parents do not determine the parent-child relationship on their own. Children also affect it (Collins, Maccoby, Steinberg, Hetherington, & Bornstein, 2000). Parents do no act the same way toward every child in the family (even though they may try) because each child is a different individual. A thoughtful, responsible child is more likely to elicit an authoritarian style. Thus, children influence the behavior of their caregivers at the same time that the caregivers are influencing them.

So far we have seen that parents can have a profound effect on the development of their children. Next, we will examine the extent to which peers also influence development.

Relationships with Other Children

At a very early age, infants begin to show an interest in other children, but the social skills required to play with them develop only gradually. Among the first peers that most children encounter are their siblings. The quality of sibling relationships can have a major impact, especially on how children learn to relate to other peers. Once children enter school peer influences outside the family increase greatly. Now they are under a great deal of pressure to be part of a peer group of friends. In peer groups, children learn many valuable things, such as how to engage in cooperative activities and how to negotiate the social roles of leader and follower (Barber, Stone, Hunt, & Eccles, 2005).

As children get older, they develop a deeper understanding of the meaning of friendship. For preschoolers, a friend is simply "someone I play with," but around age 7, children begin to realize that friends "do things" for one another. At this still egocentric age, however, friends are defined largely as people who "do things for me." Later, at about age 9, children come to understand that friendship is a two-way street and that, although friends do things for us, we are also expected to do things for them. During these early years, friendships often come and go at dizzying speeds; they endure only as long as needs are being met. It is not until late childhood or early adolescence that friendship is viewed as a stable and continuing social relationship requiring mutual support, trust, and confidence.

Successfully making friends is one of the tasks that Erikson saw as centrally important to children between the ages of 7 and 11, the stage of industry versus inferiority. At this age, children must master many increasingly difficult tasks, social interaction with peers being only one of them. Others have to do with mastering academic skills at school, meeting growing responsibilities placed on them at home, and learning to do various tasks they will need as independent adults. In Erikson's view, if children become stifled in their efforts to prepare themselves for the adult world, they may conclude that they are inadequate and lose faith in their power to become self-sufficient. Those whose industry is rewarded develop a sense of competence and self-assurance.

Recently, researchers have increasingly turned their attention to bullying. Name calling, physical attacks, and spreading damaging rumors are all common examples of bullying and all of them have negative consequences. Health problems, emotional disorders, reduced success in school, and even suicide have been linked to being the victim of bullying. Nor are the consequences short-lived: the effects can last well into adulthood (Wolke, Copeland, Angold, & Costello, 2013).

Non-Shared Environments

Most developmental psychologists believe that peer influence is just one example of a much broader class of environmental factors called the non-shared environment (R. J. Rose et al., 2003). Even children who grow up in the same home with the same parents are likely to have very different day-to-day human relationships, and this non-shared environment can have a significant effect on their development (Suitor, Sechrist, Plikuhn, Pardo, & Pillemer, 2008). One review of the research concludes that although family experiences are important, the crucial environmental influences that shape personality development are "specific to each child, rather than general to an entire family" (Plomin & Rende, 1991, p. 180).

In the United States, over half of the children between birth and third grade spend some time being regularly cared for by persons other than their parents. Some people have expressed concern that being entrusted to caregivers outside the immediate family may interfere with the development of secure attachments and put children at greater risk for emotional maladjustment. But according to the findings of one large-scale longitudinal study (NICHD Early Child Care Research Network, 1997), placing a baby in full-time daycare even in the first few months of life doesn't in itself undermine attachment. Working parents and their babies still have ample opportunity to engage in the daily give-and-take of positive feelings on which secure attachments are built. Day care, however, can be a negative factor if working parents generally provide insensitive and unresponsive care. Such behavior is, in itself, associated with insecure attachment, but these babies are even more likely to form an insecure attachment, if they also experience extensive day care, especially poor quality care or changing day-care arrangements.

One conclusion, then, is that quality of care counts (Brobert, Wessels, Lamb, & Hwang, 1997; H. Steele, 2008; Votruba-Drzl, Coley, & Chase-Lansdale, 2004). A secure, affectionate, stimulating environment is likely to produce children who are healthy, outgoing, and ready to learn, just as an environment that encourages fears and doubts is likely to stunt development. Research shows, for example, that children of working mothers who are placed in a quality daycare generally develop strong cognitive and linguistic skills and are no more likely to display behavior problems than children who stay at home (Belsky, 2006).

Sex-Role Development

By about age 3, both boys and girls have developed a gender identity - that is, a little girl knows that she is a girl, and a little boy knows that he is a boy. At this point, however, children have little understanding of what that means. A 3-year-old boy might think that if you put a dress on him, he will turn into a girl. By the age of 4 or 5, most children know that gender depends on what kind of genitals a person has. They have also acquired gender constancy, the realization that gender cannot be changed.

At quite a young age, children also start to acquire gender-role awareness, a knowledge of what behaviors are expected of males and females in their society (Bronstein, 2006). As a result, they develop gender stereotypes, or oversimplified beliefs about what the "typical" male or female are like (Sinnott, 1994; Jennifer Steele, 2003). For example, girls are supposed to be clean, neat, and careful, whereas boys are supposed to like rough, noisy, physical play. At the same time that children acquire gender-role awareness and gender stereotypes, they also develop their own sex-typed behavior: Girls play with dolls, and boys run around and wrestle with each other.

Although the behavioral differences between boys and girls are minimal in infancy, major differences tend to develop as children grow older. Boys tend to become more active and physically aggressive, and tend to play in larger groups. Girls tend to talk more, shove less, and interact in pairs. The differences can be quite dramatic. The multicultural approach demonstrates that this is a global phenomenon.

Television, Video Games, and Children

On average, American children spend 30 hours a week watching television and 1-2 hours a week playing video games (McDonough, 2009). Not surprisingly, psychologists, educators, and parents are concerned about the influence TV and video games may have on children. Indeed, the American Academy of Pediatrics (1999, 2007) recommends that children under the age of 2 should not watch television at all and that parents limit their children's time watching TV and playing video games to no more than 1 or 2 hours a day.

One concern is the violence that pervades many TV programs and video games. Children who watch 2 hours of TV daily will see about 8,000 murders and 100,000 other acts of violence by the time they leave elementary school (Kunkel et al., 1996). Even Saturday morning cartoons average more than 20 acts of violence per hour (Seppa, 1997). The great majority of video games also contain violence - often extreme violence directed toward other game characters (Dill, Gentile, Richter, & Dill, 2005). Does witnessing and, in the case of video games, participating in fictional violence make children more aggressive? And if so, does this exposure to violence account, at least in part, for the rapid rise in violent crime among adolescents?

According to two comprehensive reviews of the research, in some cases the answer appears to be "yes" (C. A. Anderson et al., 2003; Huesmann, 2007). In fact, the authors of both these reviews found that the effects of media violence can extend well into adulthood even for people who are not highly aggressive. Short-term exposure was found to increase the incidence of physically and verbally aggressive thoughts, emotions, and behaviors, whereas longitudinal studies linked exposure to media violence in childhood with aggression later in life, including physical assaults and spouse abuse. Finally, although media violence affects some people more than others, these authors concluded no one is exempt from its deleterious effects.

In addition to the issue of violence, every moment spent watching TV or playing video games takes time away from such activities as chatting with friends or playing sports, which may be more beneficial. Obesity in children has also been correlated with the amount of time spent watching TV (Vandewater, Shim, & Caplovitz, 2004). Watching too much television can also lead to a variety of sleep disturbances in children, including night wakings, daytime sleepiness, increased anxiety at bedtime, shortened sleep duration, and difficulty falling asleep (Van den Bulck, 2004).

Nonetheless, children can learn worthwhile things from watching television and playing video games. Research shows that playing interactive video games, like other forms of play, can benefit the development of cognitive skills, persistence in the face of failure, positive emotions, and social skills (Granic, Lobel, & Engels, 2014). In addition, research shows that well-designed educational television can benefit children at some ages (Bickham, Schmidt, & Huston, 2012).

ADOLESCENCE

Adolescence is the period of life roughly between ages 10 and 20, when a person is transformed from a child into an adult. This period involves not just the physical changes of a maturing body, but also many cognitive and social-emotional changes.

Physical Changes

A series of dramatic physical milestones ushers in adolescence.

Teenagers are acutely aware of the changes taking place in their bodies. Many become anxious about whether they are the "right" shape or size and obsessively compare themselves with the models and actors they see on television and in magazines. When asked what they most dislike about themselves, physical appearance is mentioned most often (Altabe & Thompson, 1994; Rathus, 2006). These concerns can lead to serious eating disorders.

Sexual Development

The visible signs of puberty - the onset of sexual maturation - occurs in a different sequence for boys and girls. In boys, the initial sign is growth of the testes at around age 11 1/2. Roughly a year later comes enlargement of the penis. Development of pubic hair takes a little longer, followed by development of facial hair. Deepening of the voice is one of the last noticeable changes of male maturation.

In females, around age 11 the breasts begin to develop and pubic hair appears. Menarche, the first menstrual period, occurs about a year or so later - at age 12 1/2 for the average American girl (Sarah Anderson, Dallal, & Must, 2003; Biro, Greenspan, & Galvez, 2012). The onset of menstruation does not necessarily mean that a girl is biologically capable of becoming a mother. Female fertility increases gradually during the first year after menarche. The same is true of male fertility. Boys achieve their first ejaculation at an average of 13 1/2, often during sleep. First ejaculations contain relatively few sperm. Nevertheless, adolescents are capable of producing babies long before they are mature enough to take care of them.

Psychologists used to believe that the beginnings of sexual attraction and desire in young people coincided with puberty, but recent research has changed this view. Hundreds of case histories put the first stirrings of sexual interest in the fourth and fifth grades. Thus, the onset of the obvious physical changes in puberty may actually be more of an ending to a process than a start.

Early and Late Developers

Individuals differ greatly in the age at which they go through the changes of puberty. Among boys, early maturing has psychological advantages. boys who mature earlier do better in sports and in social activities and receive greater respect from their peers. In contrast, although an early maturing girl may be admired by other girls, she may feel self-conscious and often dissatisfied with her developing body (Ohring, Graber, & Brooks-Gunn, 2002). Early maturing girls are also more likely to be exposed to drugs and alcohol in high school than later maturing girls (Lanza & Collins, 2002).

Adolescent Sexual Activity

Achieving the capacity to reproduce is probably the single most important development in adolescence. But sexuality is a confusing issue for adolescents in the United States. Fifty years ago, people were expected to postpone sex until they were responsible, married adults. Since then, major changes have occurred in sexual customs. In 2007, 48% of adolescents reported having had sex, and 15% reported having had sex with four or more partners.

Boys and girls tend to view their early sexual behavior in significantly different ways (T. Lewin, 1994). Fewer high school girls (46%) than boys (65%) report feeling good about their sexual experiences. Similarly, more girls (65%) than boys (48%) say that they should have waited until they were older before having sex.

Teenage Pregnancy and Childbearing

Despite a one-third decline since the early 1990s, the United States still has the highest teen birth rate in the industrialized world: more than five times the rate in France and eight times the rate in Japan (United Nations Statistics Division, 2006).

Whatever the causes, the consequences of teenage pregnancy can be devastating. The entire future of a young unmarried mother is in jeopardy, particularly if she has no parental support or is living in poverty. She is less likely to graduate from high school, less likely to improve her economic status, and less likely to get married and stay married than a girl who postpones childbearing (Coley & Chase-Lansdale, 1998). The babies of teen mothers are more likely to be of low birth weight, which is associated with learning disabilities and later academic problems, childhood illnesses, and neurological problems (Furstenberg, Brooks-Gunn, & Chase-Lansdale, 1989; K. A. Moore, Morrison, & Greene, 1997). In addition, children of teenage mothers are more likely to be neglected and abused than are children of older mothers (Coley & Chase-Lansdale, 1998; George & Lee, 1997).

The Teenage Brain

The brain continues to change throughout adolescence. Some of these changes are simply continuations of changes that began earlier in life and will continue into adulthood. Others emerge for the first time in adolescence and continue to change thereafter. Still others develop first in adolescence and then level off (Casey, 2013). Research shows that the adolescent brain is more sensitive to rewards (Galvan, 2013). The pre-frontal cortex, which is involved in self-control, is still developing (Luna, Paulsen, Padmanabhanm & Geier, 2013). These changes, in turn, affect adolescents' risk taking, ability to resist peer influence, and sensitivity to social evaluation (Albert, Chein, & Steinberg, 2013; Somerville, 2013).

Cognitive Changes

Just as bodies mature during adolescence, so do patterns of thought. Piaget (1969) viewed the cognitive advances of adolescence as an increased ability to reason abstractly, called formal-operational thought. This ability allows them to debate complex issues. Not all adolescents reach the stage of formal operations; and many of those who do, fail to apply formal-operational thinking to the everyday problems they face (Flavell, Miller, & Miller, 2002). Moreover, achieving formal-operational thinking can lead to overconfidence in new mental abilities and a tendency to place too much importance on one's own thoughts. Some adolescents also fail to realize that not everyone thinks the way they do and that other people may hold different views. Piaget called these tendencies the "egocentrism of formal operations" (Piaget, 1967).

Personality and Social Development

Adolescents are eager to establish independence from their parents, but simultaneously fear the responsibilities of adulthood. As a result, this period of development is bound to involve some stress.

How "Stormy and Stressful" is Adolescence?

Early in the 20th century, many people saw adolescence as a time of instability and strong emotions. For example, G. Stanley Hall (1904), one of the first developmental psychologists, portrayed adolescence as a period of "storm and stress," fraught with suffering, passion, and rebellion against adult authority. Recent research, however, suggests that the storm-and-stress view greatly exaggerates the experiences of most teenagers (A. R. Hines & Paulson, 2007; Casey & Caudle, 2013; Hollenstein & Lougheed, 2013). The great majority of adolescents do not describe their lives as rent by turmoil and chaos (Eccles et al., 1993). Most manage to keep stress in check, experience little disruption in their everyday lives, and generally develop more positively than is commonly believed (Bronfenbrenner, 1986; Galambos & Leadbeater, 2002). Although adolescence is inevitably accompanied by some school- and family-related stress, research indicates that effective parenting and secure attachments during adolescence are just as effective as during early childhood in helping adolescents cope during difficult times (Galambos, Barker, & Almeida, 2003).

Forming An Identity

To make the transition from dependence on parents to dependence on oneself, the adolescent must develop a stable sense of self. This process is called identity formation, a term derived from Erik Erikson's theory, which sees the major challenge of this stage of life as identity versus role confusion (Cote, 2006; Erikson, 1968). In Erikson's view, the adolescent must integrate a number of different roles - say, talented math student, athlete, and artist - into a coherent whole that "fits" comfortably. Failure to form this coherent sense of identity leads to confusion about roles.

James Marcia (1980; 2002) believes that finding an identity requires a period of intense self-exploration called an identity crisis. He recognizes four possible outcomes of this process. One is identity achievement. Adolescents who have reached this status have passed through the identity crisis and succeeded in making personal choices about their beliefs and goals. In contrast are adolescents who have taken the path of identity foreclosure. In prematurely settling on an identity chosen for them by others, they have become what others want them to be without ever going through an identity crisis. Other adolescents are in moratorium regarding their choice of an identity. They are in the process of actively exploring various role options, but they have not yet committed to any of them. Finally, some teens experience identity diffusion: They avoid considering role options in any conscious way. Some who are dissatisfied with this condition but are unable to start a search to "find themselves" resort to escapist activities such as drug or alcohol abuse. Of course, an adolescent's identity status can change over time as the person matures. Moreover, some evidence suggests that the process of identity development varies by social class or ethnic background. For instance, teens from poor families are less likely to experience a period of identity moratorium, in large part because financial constraints make it harder for them to explore many different role options (Forthun, Montgomery, & Bell, 2006; C. Levine, 2003).

Relationships With Peers

For most adolescents, peers provide a network of social and emotional support that enables greater independence from adults and facilitates the search for personal identity. But peer relationships change during adolescent years. Friendship groups in early adolescence tend to be small unisex groups, called cliques, of three to nine members. Especially among girls, these unisex friendships deepen and become more mutually self-disclosing as the teens develop the cognitive abilities to better understand themselves and one another (Holmbeck, 1994). Then, in mid-adolescence, unisex cliques usually give way to mixed-sex groups. These, in turn, are normally replaced by groups consisting of couples. At first, adolescents tend to have short-term heterosexual relationships within the group that fulfill short-term needs without exacting the commitment of "going steady" (Sorensen, 1973). Such relationships do not demand love and can dissolve overnight. But between the ages of 16 and 19, most adolescents settle into more stable dating patterns.

In the recent past, new communication technologies have had a profound effect on adolescent peer relationships. Cell phone texting, in particular, has become a true social networking tool that allows teenagers to connect with their friends instantly. Research shows that this connectivity provides a greater sense of connectedness and well-being in part because teenagers can talk about very personal issues that are otherwise difficult to discuss. In turn this heightened self-disclosure leads to closer and higher quality relationships than would otherwise be the case (Valkenberg & Peter, 2009).

Relationships With Parents

While they are still searching for their own identity and learning to think through the long-term consequences of their actions, adolescents require guidance and structure from their parents. In their struggle for independence, adolescents question everything and test every rule. Unlike young children who believe their parents know everything and are all-powerful and good, adolescents are very aware of their parents' shortcomings. It takes years for adolescents to see their mothers and fathers as real people with their own needs and strengths as well as weaknesses (Woodhouse, Dykas, & Cassidy, 2009).

The low point of parent-child relationships generally occurs during early adolescence, when the physical changes of puberty are occurring. Moreover, some significant neurological changes are also taking place. Early in adolescence the limbic regions of the brain are well developed and highly active. The limbic system is central to the experience of emotions. As adolescence progresses, the prefrontal cortex (primarily involved in reasoning and self-control) continues to mature. In turn, this ushers in "a shift from behavior that is driven by affective impulses to more regulated behavior that is guided by consideration of future personal and social consequences" (Whittle et al., 2008, p. 3652). Warm and caring relationships with adults outside the home, such as those at school or at a supervised community center, are especially valuable to adolescents during this transition period.

Some Problems of Adolescence

Declines in Self-Esteem

Adolescents are especially likely to be dissatisfied with their appearance. Adolescents who are least satisfied with their physical appearance tend also to have low self-esteem (Kuseske, 2008). Since adolescent girls are especially likely to be dissatisfied with their appearance, and because perceived attractiveness and self-esteem are more closely related for females than for males, it is no surprise that adolescent girls have significantly lower self-esteem than do adolescent boys. For boys, there is little or no decline in self-esteem during adolescence (Kling, Hyde, Showers, & Buswell, 1999).

Depression and Suicide

The rate of suicide among adolescents has increased more than 600% since 1950, though there are signs that since the mid-1990s it has begun to decrease, at least among males. Suicide is the third leading cause of death among adolescents, after accidents and homicides (Goldston et al., 2008; National Mental Health Association, 2006). Although successful suicide is more common in males than in females, twice as many females attempt suicide (National Adolescent Health Information Center, 2004).

Youth Violence

In April 1999, two teen-aged boys opened fire on their classmates at Columbine High School in Littleton, Colorado. Armed with sawed-off shotguns, a semiautomatic rifle, and a semiautomatic pistol, they killed 13 people and wounded 23 others before killing themselves.

Why did this happen? What causes children as young as 11 to kill other people and, equally often, to kill themselves? Although it is tempting to look for simple answers to these questions, the causes of youth violence are complex (Heckel & Shumaker, 2001).

Biology definitely plays a role, although its influence is certainly much more complex than simply identifying a "murderer gene." For example, researchers have identified a specific gene found in people who display a lack of compassion and an inability to control emotional impulses early in life. As adolescents and adults, their behavior is marked by higher rates of delinquency, violence, and aggression. Research has also shown that the effects of this gene on behavior may either be amplified or reduced depending on the environment in which the child is raised (Buckholtz & Meyer-Lindenberg, 2008). Other research has found that early trauma may cause a brain structure to become hyperactive, causing obsession with a single thought (such as violence) at the same time the prefrontal cortex becomes less able to control impulsive behavior (Amen, Stubblefield, Carmichael, & Thisted, 1996; Schmahl, Vermetten, Elzinga, & Bremmer, 2004).

Environment also plays a role. Most psychologists believe that the "gun culture" in which most of the youthful murderers were raised is an important factor, along with the relatively easy availability of guns (Cooke, 2004; Duke, Resnick, & Borowsky, 2005).

Severe neglect or rejection contributes as well. All of the young killers have indicated that they felt outcast and abandoned by those who should have loved them. In turn, this condition led to feelings of powerlessness and injustice (M. R. Leary, Kowalski, Smith, & Phillips, 2003). In other cases, the youths lacked adult supervision and support, often having no real attachment to even one loving and reliable adult (Garbarino, 1999).

What are the warning signs that might alert family and friends to potential violence? Lack of social connection, masking emotions, withdrawal (being habitually secretive and antisocial), silence, rage, increased lying, trouble with friends, hypervigilance, and cruelty toward other children and animals - these factors should all be cause for concern. This is especially true if they are exhibited by a boy who comes from a family with a history of criminal violence, who has been abused or bullied, who belongs to a gang, who abuses drugs or alcohol, who has previously been arrested, or who has experienced problems at school (Leschied & Cummings, 2002; Newsome & Kelly, 2006).

ADULTHOOD

The course of adult development varies because it is a result of personal decisions, circumstances, and even luck. Although developmental milestones do not occur at particular ages, certain experiences and changes eventually occur in nearly adult's life.

Love, Partnerships, and Parenting

Nearly all adults form a long-term, loving partnership with another adult at some point in their lives. Forming such a partnership is especially common in young adulthood. According to Erik Erikson, the major challenge of young adulthood is intimacy versus isolation. Failure to form an intimate partnership with someone else can cause a young adult to feel painfully lonely and incomplete.

Forming Partnerships

Almost 90% of Americans eventually get married (U.S. Bureau of the Census, 2002a), but that percentage is dropping as fewer people choose to marry. In 1960, 72% of those Americans over 18 were married; in 2012 that number had dropped to 51% (Fry, 2014). Moreover, those who do marry are waiting longer to do so. For example, in 1970, the median age of an American woman marrying for the first time was 20.8 years; this increased to 25.3 years by 2005. Similarly, for American men, the median age for first marriages was 23.2 years in 1970, increasing to 27.1 years by 2005 (U.S. Bureau of the Census, 2006).

Although heterosexual marriage is still the statistical norm in the United States, other types of partnerships exist. Cohabiting relationships are one example. In 2008, more than 5% of Americans over 18 were cohabiting compared to 3% in 1990. In 2008, more than half of Americans 30 to 49 years old say they have lived with an unmarried partner (Pew Research Center, 2010). Some of those in cohabiting relationships are gays and lesbians who seek the same loving, committed, and meaningful partnerships as their heterosexual counterparts (Kurdek, 2005). Moreover, successful homosexual relationships share the same characteristics as successful heterosexual ones: high levels of mutual trust, respect, and appreciation; sexual compatibility; shared decision making; good communication; and good conflict-resolution skills (Holmberg & Blair, 2009; Kurdek, 2005; Laird, 2003).

Parenthood

For most parents, loving and being loved by their children is an unparalleled source of fulfillment (Nelson, Kushlev, English, Dunn, & Lyubomirsky, 2013). However, the birth of the first child is also a major turning point in a couple's relationship, one that requires many adjustments. Since young children demand a lot of time and energy, parents may be left with little time or energy for each other.

Parenthood may also heighten conflicts between pursuit of careers and responsibilities at home. This outcome is especially likely among women with an active career outside the home. They may be torn between feelings of loss and resentment at the prospect of leaving their job, and anxiety or guilt over the idea of continuing to work. It is no wonder that women feel the need for their partner's cooperation more strongly during this period of life than men do (Kendall-Tackett, 2001). Contemporary fathers spend more time with their children than their fathers did, but mothers still bear the greater responsibility for both child rearing and housework.

Although homosexual couples as a group believe more strongly in equally dividing household duties than heterosexual couples do, homosexuals tend to make an exception when it comes to child rearing. Child-care responsibilities tend to fall more heavily on one member of a homosexual couple, whereas the other spends more time in paid employment (C. J. Patterson, 1995; Peplau & Beals, 2004). Notably, more than a decade of research has shown that children reared by homosexual couples do not show any significant differences in adjustment or development compared to children reared by traditional heterosexual couples (C. J. Patterson, 2009).

Given the demands of parenthood, it isn't surprising that marital satisfaction tends to decline after the arrival of the first child (Bhargava, Kassam, & Loewenstein, 2013; Luhmann, Hofmann, Eid, & Lucas, 2012). But once children leave home, many parents experience renewed satisfaction in their relationship as a couple. Rather than lamenting over their "empty nests," many couples experience an increase in positive mood and well-being (Gorchoff, John, & Helson, 2008; Stone, Schwartz, Broderick, & Deaton, 2010). For the first time in years, the couple can be alone together and enjoy one another's company.

Ending a Relationship

Intimate relationships frequently end. Although this is the case for all types of couples - married and unmarried, heterosexual and homosexual - most of the research on ending relationships has focused on married, heterosexual couples. The U.S. divorce rate has risen substantially since the 1960s, as it has in many other developed nations (T. Lewin, 1995). Although the divorce rate appears to have stabilized, it has settled at a very high level. Almost half of American marriages eventually end in divorce (U.S. Bureau of the Census, 2007).

Rarely is the decision to separate a mutual one. Most often, one partner takes the initiative in ending the relationship after a long period of slowly increasing unhappiness. Making the decision does not necessarily bring relief. In the short term it often brings turmoil, animosity, and apprehension. Most children whose parents divorce do not have long-term problems. However, in some cases divorce can have more serious effects on children. In general, younger children are at greater risk, but adolescents whose parents' divorce are at greater risk academically and in their social relationships. Children whose parents continue to be in conflict are also at greater risk (Lansford, 2009). Children adapt more successfully to divorce when they have good support systems, when the divorcing parents maintain a good relationship, and when sufficient financial resources are made available to them (Eldar-Avidan, Haj-Yahia, & Greenbaum, 2008; Sandler, Miles, Cookston, & Braver, 2008). The effects of divorce also vary with the children themselves: Those who have easygoing temperaments and who were generally well behaved before the divorce usually have an easier time adjusting (Lansford, 2009; Storksen, Roysamb, & Holmen, 2006).

The World of Work

For many young people, the period from the late teens through the early twenties is crucial because it sets the stage for much of adult life. The educational achievements and training obtained during these transitional years often establish the foundation that will shape the income and occupational status for the remainder of adult life.

Three or four generations ago, choosing a career was not an issue for most young adults. Men followed in their fathers' footsteps or took whatever apprenticeships were available in their communities. Most women were occupied in child care and housework or they pursued such "female" careers as secretarial work, nursing, and teaching. Modern career choices are far more numerous for both men and women. At the end of 2010, for example, women made up almost 47% of the labor force in the United States (U.S. Department of Labor, 2010a). Of employed women, 73% worked full-time; the rest worked part-time (U.S. Department of Labor, 2010b). The largest percentage of employed women (nearly 41%) worked in management, professional, and related occupations, while 32% worked in sales and office occupations (U.S. Department of Labor, 2010c).

Dual-Career Families

The percentage of women in the paid labor force has increased dramatically from 42% in 1973 to 54% in 2010 (U.S. Department of Labor, 2010a). The change is even greater for married women (Engemann & Owyang, 2006). This increasing role of women as economic providers is a worldwide trend (Elloy & Mackie, 2002).

Balancing the demands of career and family is a problem in many families, especially for women. Even when the wife has a full-time job outside the home, she is likely to end up doing the majority of the housework and child care. She is also likely to be aware of this imbalance and to resent it. The "double shift" - one at paid work outside the home and another at unpaid household labor - is the common experience of millions of women throughout the world. True equality - the hopeful goal of the dual-career movement - has yet to be achieved (Sabattini & Crosby, 2009). However, despite the pressures associated with the double shift, most women report increases in self-esteem and well-being when they have a paid job (Perrig-Chiello, Hutchison, & Hoepflinger, 2008).

Cognitive Changes

Only recently have researchers begun to explore the ways in which adult and adolescent thinking differ. Nonetheless, a few conclusions have begun to emerge. Although adolescents are able to test alternatives and to arrive at what they see as the "correct" solution to a problem, adults gradually come to realize that there isn't a single correct solution to every problem - there may, in fact, be no correct solution, or there may be several. Adults are also more practical: They know that a solution to a problem must be realistic as well as reasonable. No doubt these changes in adult thinking derive from greater experience of the world. Dealing with the kinds of complex problems that arise in adult life requires moving away from the literal, formal, and somewhat rigid thinking of adolescence and young adulthood (G. Goldstein, 2004).

Most measurable cognitive changes during adulthood do not simply involve a rise or fall in general ability. Instead, for most people, such cognitive skills as vocabulary and verbal memory increase steadily through the sixth decade of life. In contrast, perceptual speed (the ability to make quick and accurate visual discriminations) and the ability to perform mathematical computations show the largest decrease with age, with the former beginning to decline as early as age 25, and the latter starting to decline around age 40 (Schaie & Willis, 2001; Schaie & Zanjani, 2006).

For optimal cognitive development, mental exercise is a necessity. Although some decline in cognitive skills is inevitable as people age, the decline can be minimized if people stay mentally active (Stine-Morrow, Parisi, Morrow, & Park, 2008; R. S. Wilson et al., 2003).

Midlife

Psychological health generally improves in adulthood. And adolescents with better psychological health tend to improve even further in adulthood (C. J. Jones & Meredith, 2000; Shiner, Masten, & Roberts, 2003). Both men and women tend to show increased emotional stability, warmth, self-confidence, and self-control with age (B. W. Roberts & Mroezek, 2008). One meta-analysis of several studies found that on average, conscientiousness, emotional stability, agreeableness, and openness to new experience all increased in middle adulthood (B. W. Roberts, Walton, & Viechtbauer, 2006). In short, for most people midlife is a time of active change and involvement in multiple pursuits (Willis, Martin, & Rocke, 2010). Such findings suggest that the majority of people are successfully meeting what Erik Erikson saw as the major challenge of middle adulthood: generativity versus stagnation. Generativity refers to the ability to continue being productive and creative, especially in ways that guide and encourage future generations. For those who fail to achieve this state, life becomes a meaningless routine, and the person feels stagnant and bored.

Feelings of boredom and stagnation in middle adulthood may be part of what is called a midlife crisis. The person in midlife crisis feels painfully unfulfilled and ready for a radical, abrupt shift in career, personal relationships, or lifestyle. Research shows, however, that the midlife crisis is not typical; most people do not make sudden dramatic changes in their lives in mid-adulthood (M. E. Lachman, 2004; Strenger, 2009). In fact, one large-scale study found that the majority of middle-aged adults reported lower levels of anxiety and worry than young adults, and generally felt positively about their lives. Daniel Levinson, who studied personality development in men and women throughout adulthood (Levinson, 1978, 1986, 1987), preferred the term midlife transition for the period when people tend to take stock of their lives. Many of the men and women in his studies, confronted with the first signs of aging, began to think about the finite nature of life. They realized that they may never accomplish all they had hoped to do, and they questioned the value of some of the things they had accomplished so far. As a result, some gradually reset their life priorities, establishing new goals based on their new insights.

LATE ADULTHOOD

During the 20th century, the percentage of Americans over 65 more than tripled; and those over 85 now represent the fastest-growing segment of the population (National Institute on Aging, 2006). In the 2010 census, more than 40 million Americans were over age 65; by the year 2050, there may be nearly 90 million in this age group (U.S. Bureau of the Census, 2010).

However, a sizable gender gap exists in life expectancy. The average American woman today enjoys a life span that is 5.2 years longer than that of the average American man, but that difference has been shrinking since 1980 as the life expectancy of males increases more rapidly than that of females (Minino, Heron, & Smith, 2006). The reasons for this gender gap are still unclear, but likely factors include differences in hormones, exposure to stress, health-related behaviors (Moller-Leimkuhler, 2003), and genetic makeup.

There is also a gap in life expectancy between Whites and African Americans in the United States, although that gap also is closing. The average White American child born today is likely to live 5 years longer than the average African American child (Minino, Heron, & Smith, 2006). This difference seems to stem largely from socioeconomic disparities.

Because older adults are becoming an increasingly visible part of American society, it is important to understand their development. Unfortunately, our views of older adults are often heavily colored by myths. For example, many people believe that most older adults are lonely, poor, and troubled by ill health. The false belief that "senility" is inevitable in old age is another damaging myth, as is the belief that most older adults are helpless and dependent on their families for care and financial support. Research contradicts these stereotypes. Increasingly, people age 65 and over are healthy, productive, and able (D. M. Cutler, 2001; Manton & Gu, 2001). However, research also shows that these myths can become self-fulfilling prophecies. For example, older adults who believe they are destined to be troubled by physical losses are likely to do what is necessary to prevent those losses (Wurm, Warner, Ziegelmann, Wollf, & Schuz, 2013).

Physical Changes

Most people in midlife have few serious illnesses. However, in middle adulthood and continuing through late adulthood, physical appearance changes, as does the functioning of every organ in the body. The hair thins and turns white or gray. Bones become more fragile. Circulation slows, blood pressure rises, and because the lungs hold less oxygen, the older adult has less energy. Vision, hearing, and the sense of smell all become less acute (Cavanaugh & Blanchard-Fields, 2005).

We do not yet know why physical aging happens (Pankow & Solotoroff, 2007). Whatever the ultimate explanation for physical decline, many factors affect adults' physical well-being. Among these are things they can control, such as diet, exercise, and health care. Attitudes and interests also matter. People who have a continuing sense of usefulness, who maintain old ties, develop new interests, and feel in control of their lives have the lowest rates of disease and the highest survival rates (R. N. Butler, Lewis, & Sunderland, 1998). Self-perceptions also matter: Adults who enter late adulthood with negative beliefs about aging have more health problems and die much sooner than those who begin late adulthood with positive expectations (Levy, 2009; Levy, Zonderman, Slade, & Ferrucci, 2009).

in fact, despite the normal physical decline that occurs in late adulthood, a survey of 355,334 Americans age 18 to 85 showed that psychological well-being increased dramatically beginning in the early 50s (Stone, Schwartz, Broderick, & Deaton, 2010). Personal relationships also improve with age (Fingerman & Charles, 2010).

Social Development

Far from being weak and dependent, most men and women over age 65 live apart from their children and outside nursing homes. The ability to live independently and take enjoyment from everyday situations is an important predictor of satisfaction among the elderly (Rioux, 2005). Contrary to some stereotypes, research shows that adults tend to get happier as they grow older (Isaacowitz & Blanchard-Fields, 2012). Moreover, those who remain physically and mentally active, travel, exercise, and attend meetings are more likely to report being happier and more satisfied with their lives than those who stay at home (L. K. George, 2001). Sex continues to be an important factor in their quality of life (Hillman, 2012). Maintaining social relationships has also been shown to be closely associated with successful aging (Cherry et al., 2013).

Retirement

In late adulthood, most people retire from paid employment. Individual reactions to this major change vary widely, partly because society has no clear idea of what retirees are supposed to do (Schlossberg, 2004). Men generally see retirement as a time to slow down and do less, whereas women often view it as a time to learn new things and explore new possibilities (Helgesen, 1998). This difference can cause obvious problems for retired people.

Of course, the nature and quality of retired life depend on financial status. If retirement means a major decline in a person's standard of living, that person will be less eager to retire and will lead a more limited life after retirement. Another factor in people's attitudes toward retirement is their feelings about work. People who are fulfilled by their jobs are usually less interested in retiring than people whose jobs are unrewarding (Atchley, 1982). Similarly, people who have very ambitious, hard-driving personalities tend to want to stay at work longer than those who are more relaxed.

Sexual Behavior

A common misconception is that elderly people have outlived their sexuality. This myth reflects our stereotypes. To the extent that we see them as physically unattractive and frail, we find it difficult to believe that they are sexually active. Although the sexual response of older people is slower and they are less sexually active than younger people, the majority can and do enjoy sex and have orgasms (Herbenick et al., 2010; Lindau et al., 2007). Similar to younger people, a high level of self-esteem and good physical health are important predictors of sexual activity and satisfaction in the elderly (Kontula & Haavio-Mannila, 2009).

Cognitive Changes

Healthy people who remain intellectually active maintain a high level of mental functioning in old age. In particular, learning new, challenging skills over an extended period has been shown to have a beneficial effect on memory. Since the aging mind works a little more slowly, certain types of memories are more difficult to store and retrieve and the ability to process and attend to information does gradually decline. For the most part, however, these changes do not interfere significantly with the ability to enjoy an active, independent life. In fact, research has shown that because older adults tend to focus more on positive than negative events, they are better able to cope with the inevitable ups and downs of life than are adolescents or younger adults. Moreover, older adults who stay both mentally and physically active generally experience significantly less cognitive decline than those who are inactive. Training and practice on cognitive tasks can also help reduce the decline in cognitive performance in later adulthood, though the benefits of training are often limited only to the skills that are practiced.

Alzheimer's Disease

For people suffering from Alzheimer's disease, the picture is quite different. The disease causes brain changes resulting in the progressive loss of the ability to communicate and reason.

According to current estimates, about 10% of adults over age 65 and nearly half of adults over age 85 suffer from Alzheimer's disease. Alzheimer's usually begins with minor memory losses, such as difficulty in recalling words and names or in remembering where something was placed. As it progresses - a process that may take anywhere from 2 to 20 years - personality changes are also likely.

First, people may become emotionally withdrawn or flat. Later, they may suffer from delusions, such as thinking that relatives are stealing from them. These people become confused and may not know where they are or what time of day it is. Eventually, they lose the ability to speak, to care for themselves, and to recognize family members. Eventually, Alzheimer's is fatal.

There is no known cure nor can it be prevented, but breakthroughs in research are occurring so fast that a drug to slow the progress of the disorder or even a vaccine to prevent it may be developed in the near future.

Facing the End of Life

Fear of death is seldom a central concern for people in later adulthood. In fact, such fear seems to be a greater problem in young adulthood or in middle age, when the first awareness of mortality coincides with a greater interest in living.

But elderly people do have some major fears associated with dying. They fear the pain, indignity, and depersonalization that they might experience during a terminal illness, as well as the possibility of dying alone. They also worry about burdening their relatives with the expenses of their hospitalization or nursing care. Sometimes, too, relatives are not able to provide much support for the elderly as they decline, either because they live too far away or because they may be unable to cope either with the pain of watching a loved one die or with their own fears of mortality.

Stages of Dying

In her classic work, the late psychiatrist Elisabeth Kubler-Ross (1926-2004) interviewed more than 200 dying people of all ages to try to understand death's psychological aspects. She described a sequence of five stages people pass through as they react to their own impending death:

1) Denial - The person denies the diagnosis, refuses to believe that death is approaching, insists that an error has been made, and seeks other, more acceptable opinions or alternatives.

2) Anger - The person now accepts the reality of the situation but expresses envy and resentment toward those who will live to fulfill a plan or dream, asking "Why me?" Anger may be directed at the doctor or directed randomly. The patience and understanding of other people are particularly important at this stage.

3) Bargaining - The person desperately tries to buy time, negotiating with doctors, family members, clergy, and God in a healthy attempt to cope with the realization of death.

4) Depression - As bargaining fails and time is running out, the person may succumb to depression, lamenting failures and mistakes that can no longer be corrected.

5) Acceptance - Tired and weak, the person at last enters a state of "quiet expectation," submitting to fate.

According to Kubler-Ross, Americans have a greater problem coping with death than people in some other cultures. She observed that some cultures are death affirming.

For example, the Trukese of Micronesia start preparing for death at age 40. One of the most important national holidays in Mexico is El Dia de los Muertos (Day of the Dead), which is a celebration of remembrance that often involves parties, dancing, and even picnics. The living can pay tribute to relatives who have died, and the deceased relatives can once again spend time with the living.

In contrast, American culture is death denying. We dye our hair and spend fortunes on plastic surgery to hide our wrinkles. We also shelter children from knowledge of death and dying. By trying to protect them from these unpleasant realities, however, we may actually make them more fearful of death.

Some observers have found fault with Kubler-Ross's model of dying. Most of the criticisms have focused on her methodology. She studied only a relatively small sample of people and provided little information about how they were selected and how often they were interviewed. Also, all her patients were suffering from cancer. Does her model apply as well to people dying from other causes? Finally, some critics question the universality of her model. Death itself is universal, but reactions to dying may differ greatly from one culture to another.

Despite these questions, there is nearly universal agreement that Kubler-Ross deserves credit for pioneering the study of the transitions that people undergo during the dying process. She was the first to investigate an area long considered taboo; and her research has made dying a more "understandable" experience.

Widowhood

The death of one's spouse may be the most severe challenge of late adulthood. People often respond to such a loss with initial disbelief, followed by numbness. Only later is the full impact of the loss felt, which can be severe. The incidence of depression rises significantly following the death of a spouse. One long-term study revealed that older widows and widowers had a higher incidence of dying within 6 months after the death of their spouse than other married persons of their age. Moreover, this death rate was much higher for widowers than for widows and for people between the age of 55 and 70 than for those over the age of 70. After this initial 6-month period however, the mortality rate of both the men and the women fell gradually to a more normal level.

For somewhat different reasons, then, the burden of widowhood is heavy for both men and women. But because women have a longer life expectancy, there are many more widows than widowers. Thus, men have a better chance of remarrying. More than half the women over 65 are widowed, of whom half will live another 15 years without remarrying.